Mini-map illusion

Okay, now here is one that may be difficult since you can't look at what I already have but, here it is anyway. I have a program(C++) drawing a graph (using TPaintbox in BCB 6). It reads in a text file and graphs it...but thats not important. The graph is of a triangle and points plotted within it. What I would like to do is have a little "mini map" or miniture model of the triangle to the side, and have the user move thier cursor over it to zoom up on any particular part. I'm really not sure how to go about this, but hopefully it's simpler than I think it is.